From the Sony Camera Channel, a video highlighting the a7R III high-resolution, 4K video.
with this description
Full pixel readout in the Super 35 mm mode, without the need for pixel binning, makes it possible to condense 5K (15-megapixel) data into high resolution, extraordinarily beautiful 4K movies with minimal moiré and jaggies. Advanced image processing also allows full-frame 4K movie recording with dramatically improved image quality at mid to high sensitivities. Super 35mm or full-frame recording can be selected as required. Fast Hybrid AF performance during movie recording has been refined, providing a wide AF area that is similar to that provided for still images. AF now accurately locks onto moving subjects over a wider area.
And, the advancement in the Mark III is a more accurate autofocus while shooting video.
The a7R III launched last week and what you need to know is it’s a camera for just about everyone, and that’s the main point, compared to the also-launched this year a9.
It has a 42mp sensor, so the resolution is traditionally for portrait work but its fast enough for use in all situations.
The Sony a7R III is available for pre-order now from Amazon for $3198 and ships in November. Expect the first stock to sell out.